At 277 sites they placed the frame in the grass and counted all of the plant species within it. Their research, published in Global Change Biology, found that across Switzerland, the average number of plant species on agricultural grassland has fallen by 26% over the last century. This allows their impact on species diversity to be studied and compared with other factors such as climate change, the researchers say. More nitrogen fertiliser, more frequent mowing and highly productive plants displacing native species all reduce plant diversity, the analysis shows. A list of all found plant species saw 117 losers and just six winners.
